mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
47 lines
1.1 KiB
C
47 lines
1.1 KiB
C
/*
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Copyright (C) 2014 Fredrik Johansson
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This file is part of Arb.
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Arb is free software: you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb_modular.h"
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void
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psl2z_mul(psl2z_t h, const psl2z_t f, const psl2z_t g)
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{
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if (h == f || h == g)
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{
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psl2z_t t;
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psl2z_init(t);
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psl2z_mul(t, f, g);
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psl2z_swap(t, h);
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psl2z_clear(t);
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return;
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}
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fmpz_mul(&h->a, &f->a, &g->a);
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fmpz_addmul(&h->a, &f->b, &g->c);
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fmpz_mul(&h->b, &f->a, &g->b);
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fmpz_addmul(&h->b, &f->b, &g->d);
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fmpz_mul(&h->c, &f->c, &g->a);
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fmpz_addmul(&h->c, &f->d, &g->c);
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fmpz_mul(&h->d, &f->c, &g->b);
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fmpz_addmul(&h->d, &f->d, &g->d);
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if (fmpz_sgn(&h->c) < 0 || (fmpz_is_zero(&h->c) && fmpz_sgn(&h->d) < 0))
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{
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fmpz_neg(&h->a, &h->a);
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fmpz_neg(&h->b, &h->b);
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fmpz_neg(&h->c, &h->c);
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fmpz_neg(&h->d, &h->d);
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}
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}
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